Vapor electric device



March 1950 M. MIDDLETON, JR 2,499,759

VAPOR ELECTRIC DEVICE Filed May 7, 1949 42 m Fig.|. 3 47 g 48 3? 42 I5 38 I 3 7 4O 3 4 as 3? 34 8 Insulation I ll Insulufion x 7 Insulation g WITNESSES: INVENTOR MurshollMxddleTomdr.

ATTORNEY Patented Mar. 7, .1950

VAPOR ELECTRIC DEVICE Marshall Middleton, J r., Pittsburgh, Pa., assignor to. West nghouse Electric Corporation, East Pittsburgh; Pa., a corporation of Pennsylvania Application May 7, 1949, Serial No. 92,051

y invention. relates to a; vapor electric device and particularly to a ,lcaddn bushing for such a device.

In the construction and. maintenance of vaporelectric devices, considerable difliculty has been encountered in providing lead-in bushings for the various electrodes, particularly the anodes which will maintain sufficient vacuum tightness during operation.

It has been difficult to provide a construction which will maintain vacuum tightness and at the same time support the weight .ofv the lead-in conductors as. well as the electrodes connected thereto. Not only must the bushings; be capable of maintaining the static pressures caused by the weight of the equipment, but also must withstand kinetic pressures due to motion of the device or to electrostatic or magnetic disturbances caused by operation of the device.

It has heretofore been proposed to provide a heavy pressed glass bushing to maintain the mechanical stresses of such a. bushing and to seal into the bushing material thin sealing strips which maintain the vacuum tightness. Considerable difficulty has been encountered because of the stresses set up, either during construction of the device orin the mechanical clamping of the bushing to the container of the device.

It is, accordingly, an object of my invention to provide a bushing capable. of withstanding stresses not only of construction but of clamping the devices together. Instead of sealing the metal portions into the body of the bushing, I prefer to pressure mold them in place so that the seal between the bushing material and the sealing metals is a portion of the pressure molding operation.

In order to eliminate the clamping stresses, I have provided two clamping surfaces at substantially right angles to each other so that the application of clamping forces is substantially compensated in the device without resulting stress on the material.

Other objects and advantages of my invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing in which:

Figure 1 is a sectional elevation of a vaporelectric device embodying my invention; and

Fig. 2 is an enlarged view of the details of the mechanical clamp and vacuum seal.

In an exemplary embodiment of my invention, the valve comprises a container I having a substantially cylindrical wall 2, one end of which 5 Claims, (01.250-275) is closed by a suitable header 3, preferably me- 55 chanically detachable from the remainder of the container l as by bolts 4 although it may be permanently secured as by welding. A cathode pool 5 of vaporizable reconstructable material, usually mercury, is provided in the bottom of the container I and an ignition control device, such as a make-alive electrode 6, is arranged in permanent contact with the pool 5 of cathode material and is provided with a suitable lead-in bushing l for the application of control potential.

Usually, a pumping connection 8 is provided in some portion of the container I, preferably a portion remote from the cathode pool 5, to permit ready evacuation of the container I and, if desired, the maintenance of such evacuation during the life of the container. If the valve is to be of the pumped type, that is, having evacuation maintained by the application of pumps, it is desirable to provide a mercury shield 9 to prevent droplets of mercury from impinging on the various electrodes in the valve.

In spaced insulated relation to the cathode 5 is a cooperating anode l0, usually constructed of graphite and preferably provided with shields such as the anode shield ii and the cathode shield i2, both of which are also preferably constructed of graphite and supported from the container walls, preferably by insulated supports such as I3 and 54. If desired, the anode shield H may be provided with a lead-in connection !5 for the application of control potential to the anode shield H.

The lead-in conductor It for the anode I 0 is sealed to the header 3 by means of my improved vitreous seal 20. This seal 20 comprises a substantially cylindrical body portion 2| of relatively great thickness and preferably of pressure molded glass construction.

The cylindrical body portion 2! of the bushing is made as a unitary device by inserting sealing collars or flanges for both the lead-in seal and the container seal into the molds 50 that when the glass is pressed into position in the mold the sealing metal, both the lead-in collar 33 and the sealing flange 34 are embedded and joined with the vitreous body material so that the construction is substantially unitary. A mechanical clamping flange 35 is provided around the vitreous body 2| and provided with outwardly sloping surfaces 36 and 3'! which converge toward the periphery 38 of the flange 35 to provide two opposed clamping surfaces 36 and 3! substantially at right angles to each other. A seating surface 39 of the header 3 is provided which is complementary to the seating surface 31, of the clamping flange 35 and is generally held in place by a mechanical clamp, usually a clamping ring 40 having a clamping surface 4| complementary to surface 36 so that the Stresses applied in clamping the flange 35 to the seating surfaces 39 and 4| are at right angles to each other and substantially cancel out so that no stresses reside in the vitreous body 2| after it is clamped in place.

To provide a seal between the vitreous body 2| and the header 3 of the container l, the sealing disk 34, which was cast into the periphery of .the sealing flange 35, is welded or integrally united to a boss 42 provided on the header 3. By extending outwardly from the periphery of the flange 35 between the clamping surfaces 36 and 31, the sealing disk 34 can be made of suflicient diameter that-the heating incidental to welding the disk 34 to the boss 42 is not transmitted to the vitreous body 2| in suflicient quantities to cause warping or cracking. Also, the disk 34 is of sufficient size as .to be relatively flexible so that stresses are not readily transmitted by the disk 34 to the vitreous body 2 I.

The seal between the lead-in conductor l6 and the vitreous body 2| is made by means of the collar 33 embedded in the vitreous material and surrounding an opening 45 in which the lead-in H is mechanically locked by any suitable means herein illustrated as an inturned collar or flange 46 on the vitreous body 2| to which the anode stem it or conductor is mechanically connected by means of a threaded nut 4'! and collar 48 combination. Outside of the mechanical connection,

a disk Or washer 49 of sealing material is inte-.

grall united as by welding or brazing to the lead-in conductor l5, and the exterior periphery of the washer 49 is welded or integrally united to the collar 33 embedded in the vitreous material.

While I have shown a preferred embodiment of I substantially cylindrical cast vitreous body having a longitudinal passage therethrough, a collar of sealing metal embedded in said body about said passage, a conductor extending through said passage, a mechanical connection retaining said conductor in fixed relation in said passage, a seal an annular seating flange around said body, the

oppositefaces of said flange converging from the 'bodyto the periphery of the flange providing angularly disposed seating surfaces and an annular sealing disk embedded in said flange between said seating surfaces.

3. A lead-in assembly for a metal tank device comprising a tapered annular seat in said tank, a molded vitreous bushing having a passage therethrough,-'- a -conductor mechanically secured in said passage, asubstantiallycylindrical sealing flange cast into said bushing substantially coaxial with the passage, a vacuum'seal between said cylindrical flange and the conductor, a seating flange on said bushing, a pair of converging seating surfaces on saidflange, a sealing disk cast into said flange between said seating surfaces, a tapered pressure ring mechanically holding said seating flange on said annular seat and a vacuum seal between said disk and said tank.

4. An anode bushing comprising a cast vitreous body having a passage therethrough for receiving a conductor, a collar of sealing metal cast into said body around one end of said passage, a seating flange around said body, the opposed faces of said flange being oppositely sloped to provide oppositely disposed bevel seats and an annular sealing disk cast into said flange and extending beyond the periphery thereof.

5. A lead-in asembly for a metal tank device comprising a cast vitreous insulator having a passage therethrough, a conductor extending through said passage, mechanical means securing said conductor firml in said passage, a collar of sealing metal embedded in said insulator around said passage, a vacuum seal between said collar and said conductor, a seating flange around said insulator, a tapered seating surfaces on said 50 flange, a complementary seating surface on said No references cited. 

